The present invention relates to a device for turning an electric motor an and off, in particular in a power tool, preferably with housing dimensions in compliance with European standards.
For the operation of power tools press switches are known already which serve to effect switching by means of a control element in opposition to the force of a spring effective in the turn-off direction. The control element is used to turn on the current for the electric motor of the power tool by means of a mobile contact bridge closing respective pairs of terminal contacts.
In the prior art appliance switches of this type the contact pressure depends on a predetermined travel of the control element or the pusher stroke, respectively. What has turned out to be inexpedient in these devices is the fact that insufficient or slow pressure for turning on the appliance switch a contact pressure is created which is too low and which results in a high contact consumption and hence in premature wear. When the appliance is turned off high contact consumption occurs, too, as a result of an electric arc when the contact pressure, which decreases until the contacts are opened, persists for a moment during opening.